<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>
<body>
    <script>
        /* 返回值就是函数的执行结果，js中函数可以没有返回值 
           使用return语句后，返回值后面的语句不会执行
        */    
        function show(){
            return "hello world"
            console.log(3)  //无返回值
        }
        console.log(show())  //hello world
        function go(x){
            console.log(x)
        }
    </script>
</body>
</html>